Response

Confusion

You have something confusing going on. I was
searching for some articles on fuel injection tuning back in 1999 and I found a
few of them, one in particular issue 19 page 81, Electronic Engine Management
Part I dated March 2, 1999, in the technical features section. When I click on
it, it brings me to a much later article, issue 419 February 26, 2007 article.
Why is that? Actually this happens for issue 20, and issue 21. They bring you to
Issue 420, and 421. Can you explain what is going on? Can you provide me with
the 1999 articles?

Greg FischerUnited States

Where material has been republished, the
original article number is updated.

Aero

I'm writing in response to Julian Edgar's "Car
Aerodynamics Have Stalled" piece. I just wanted to point out my research aimed at defeating aerodynamicpressure drag on cars, planes and other vehicles.
You can read more at my website: www.pressurethrust.com

Dave BirkenstockUnited States

LS400 Tuning

I have a ‘90 Celsior and I'm very interested in
the Digital Fuel Adjustor. I realise that it will have to go on the pre cat
oxygen sensor as the Karmen Vortex airflow meter uses a frequency signal.
Julian mentioned in one of his articles that the closed loop on his LS stayed in
longer than most before going to open circuit; just how far up the rev range was
that? 80 percent of the time I'm never over 3000 RPM so if it stayed on the oxy
sensors to around those revs, setting the DFA up on the oxy sensors would be
enough? Also how will the ECU handle the DFA only being on one of the two
pre-cat oxy sensors or do I need to use two DFA's seeing as the engine really
runs as two 4 cylinder engines? Is it possible to convert the frequency to
volts, put it through the DFA and then convert it back, as well as having
another unit on the oxy sensors? Any help would be greatly appreciated. As a
side note I will most definitely be running one of the pulse units on my power
steering !!!...Can't wait !! Julian how did you handle it when you sold
one of the best put together cars in the world? I feel "Safe" in my solid as a
rock Celsior, now you drive a micro sandwich???? Or do you just not go down that
road?Richard O'NeilAustralia

We suggest that using the Digital Fuel Adjuster on
the oxygen sensors will not be successful – we have tried it and it didn’t work.
Julian Edgar has owned as many small cars as large cars.

No Return Line

Just read your
article 'Boosting Injector Flow' that covers vehicles with a return fuel line.
Will you be looking at vehicles with no fuel return line? eg MX5 after 2001

Airbag Modifications

Modifications
to airbags! This is exactly the sort of "nobody else even thinks of writing
about this" stuff that keeps me subscribed. Keep up the good work.

Patrick McAuliffeAustralia

Fusion Intercooler

I was reading "The Fusion Intercooler" article
and this got me thinking. It is said in the article that intercoolers
under most boost conditions (road use) simply absorb more heat like a passive
heatsink than actually pass the heat immediately on to the air (this happens
over time off-boost, as described). Also the article notes the material
property of specific heat.

In my personal studies of computer cooling
I've learned that the lower the specific heat value of the material in an active
heatsink (like a radiator), the quicker it passes the heat to the air going
through it. This is why copper (specific heat value of 0.39 kJ/kg/degree
C) is used in high performing PC active heatsinks over the cheaper aluminium
(specific heat value of 0.94 kJ/kg/degree C).

So my question is, why is
it that copper intercoolers are not used in cars for the same reason? Now
I must confess I don't know very much about car technology, most of what I do
know I've actually learned from reading AutoSpeed. But still thus far I've
never seen or heard about a copper intercooler or radiator on a car. Why
is aluminium so often chosen? I can think of two reasons, the greater
price and weight of copper, but I would imagine to some people squeezing more
performance out of a car could be done well enough to outweigh these. Or
perhaps aluminium also resists corrosion better? I'm not sure.

Do enlighten me.

J. Nicholas
SarrisUnited States

We think you’re confusing the importance of
specific heat and conductivity. But in regard to radiators, millions (billions?)
of cars have been built with copper radiators – but when copper was relatively
cheaper and aluminium more expensive.

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